All The World's Primates

The First Study of the Bale monkey, a Species Unique to the Central Mountains of Ethiopia

June 01, 2011

Juvenile Bale Monkey

Addisu Mekonnen and Anagaw Atickem

Bale monkey (Chlorocebus djamdjamensis) is an Old world monkey endemic to the Bale Mountains of Ethiopia. Discovered in 1902, little was known about the ecology and distribution of the species. Our PCI funded research aims to provide reliable data on the distribution and basic ecology of the species vital for conservation efforts. We began by using high resolution satellite images to find potential sites for the Bale monkey survey. This lead to the discovery of three new Bale monkey populations.

The results of our research show that the Bale monkey is found exclusively in the bamboo forest. Bale monkeys feed on 11 plant species but bamboo compromises about 77% of their diet. They consumed mainly bamboo young leaves. Thus, bamboo is a key resource for the species. This is especially surprising given that all of their close relatives including vervet monkeys and green monkeys are very adaptable generalists who eat diverse, varied diets and occupy a wide variety of habitats. This habitat specialist behavior of the Bale monkey on bamboo forest makes the species vulnerable.

The amount of bamboo forest is small and it is cut by local people. Currently, we are continuing to survey for Bale monkey populations in Sidamo highlands areas, south west of Bale Mountains. Additionally, we are collaborating with the University of Oslo to determine the genetics of this taxon. We strongly recommended a conservation action plan be developed for all the Bale monkey populations.